1 files changed, 23 insertions, 7 deletions

diff --git a/kernel/kmod.c b/kernel/kmod.c
index f044f8f57703..b46dbb908669 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -118,10 +118,10 @@ EXPORT_SYMBOL(request_module);
 struct subprocess_info {
         struct work_struct work;
         struct completion *complete;
+        struct cred *cred;
         char *path;
         char **argv;
         char **envp;
-        struct key *ring;
         enum umh_wait wait;
         int retval;
         struct file *stdin;
@@ -134,19 +134,20 @@ struct subprocess_info {
 static int ____call_usermodehelper(void *data)
 {
         struct subprocess_info *sub_info = data;
-        struct key *new_session, *old_session;
         int retval;
 
-        /* Unblock all signals and set the session keyring. */
-        new_session = key_get(sub_info->ring);
+        BUG_ON(atomic_read(&sub_info->cred->usage) != 1);
+
+        /* Unblock all signals */
         spin_lock_irq(&current->sighand->siglock);
-        old_session = __install_session_keyring(new_session);
         flush_signal_handlers(current, 1);
         sigemptyset(&current->blocked);
         recalc_sigpending();
         spin_unlock_irq(&current->sighand->siglock);
 
-        key_put(old_session);
+        /* Install the credentials */
+        commit_creds(sub_info->cred);
+        sub_info->cred = NULL;
 
         /* Install input pipe when needed */
         if (sub_info->stdin) {
@@ -185,6 +186,8 @@ void call_usermodehelper_freeinfo(struct subprocess_info *info)
 {
         if (info->cleanup)
                 (*info->cleanup)(info->argv, info->envp);
+        if (info->cred)
+                put_cred(info->cred);
         kfree(info);
 }
 EXPORT_SYMBOL(call_usermodehelper_freeinfo);
@@ -240,6 +243,8 @@ static void __call_usermodehelper(struct work_struct *work)
         pid_t pid;
         enum umh_wait wait = sub_info->wait;
 
+        BUG_ON(atomic_read(&sub_info->cred->usage) != 1);
+
         /* CLONE_VFORK: wait until the usermode helper has execve'd
          * successfully We need the data structures to stay around
          * until that is done.  */
@@ -362,6 +367,9 @@ struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,
         sub_info->path = path;
         sub_info->argv = argv;
         sub_info->envp = envp;
+        sub_info->cred = prepare_usermodehelper_creds();
+        if (!sub_info->cred)
+                return NULL;
 
   out:
         return sub_info;
@@ -376,7 +384,13 @@ EXPORT_SYMBOL(call_usermodehelper_setup);
 void call_usermodehelper_setkeys(struct subprocess_info *info,
                                  struct key *session_keyring)
 {
-        info->ring = session_keyring;
+#ifdef CONFIG_KEYS
+        struct thread_group_cred *tgcred = info->cred->tgcred;
+        key_put(tgcred->session_keyring);
+        tgcred->session_keyring = key_get(session_keyring);
+#else
+        BUG();
+#endif
 }
 EXPORT_SYMBOL(call_usermodehelper_setkeys);
 
@@ -444,6 +458,8 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info,
         DECLARE_COMPLETION_ONSTACK(done);
         int retval = 0;
 
+        BUG_ON(atomic_read(&sub_info->cred->usage) != 1);
+
         helper_lock();
         if (sub_info->path[0] == '\0')
                 goto out;